C:/programs/etirm/src/Start3PL.h File Reference

Compute item parameter estimate starting values for one, two, or three-parameter logistic model using nonlinear regression for each item based on an estimated ability for each examinee. Ability estimates are obtained using the PROX method. More...

#include "etirm/etirmtypes.h"
#include <set>
#include <cmath>

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Namespaces
namespace	etirm
Functions
template<class RI, class II>
void	etirm::PersonMoments (RI iresp, II iitem, RealVector &itemdiff, Response notPresentedResponse, Real *mean, Real *variance)
	Compute mean and standard deviation of logit item difficulty over items responded to by an examinee.
template<class IE, class RI>
void	etirm::ItemMoments (int num_examinees, IE begin_examinee, int item, RealVector &abilities, Response notPresentedResponse, double *mean, double *variance)
	Compute mean and standard deviation of person ability over examinees who reponded to an item.
template<class EI, class RI, class II>
void	etirm::PROX (int numItems, bool useAll, EI begin_examinee, EI end_examinee, II begin_item, Response notPresentedResponse, RealVector &itemdiff, RealVector &abilities)
	Compute Rasch item difficulties and examinee abilities using the Normal Approximation Estimation Algorithm (PROX).
template<class I>
void	etirm::AssignItemNR (int n, RealVector::iterator itemTheta, RealVector::iterator nVec, RealVector::iterator rVec, I *item)
	Assigns individual examinee thetas into discrete latent variable categories and updates expected counts n and r for item M-step.
template<class RI, class MI, class EI, class I, class II>
int	etirm::StartingValues3PL (MI begin_min, EI begin_examinee, EI end_examinee, II begin_item, II end_item, Response notPresentedResponse, bool useAll=false, int baseGroup=1, std::set< I * > *calc_items=0)
	Computes starting values for a sequence of items modeled with the three-parameter logistic model.
Variables
const Real	etirm::invalidLogit = 10000.0
	value to indicate invalid logit (e.g., logit(1))

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Detailed Description

Compute item parameter estimate starting values for one, two, or three-parameter logistic model using nonlinear regression for each item based on an estimated ability for each examinee. Ability estimates are obtained using the PROX method.

Estimation Toolkit for Item Response Models (ETIRM) http://www.smallwaters.com/software/cpp/etirm.html

Author(s): Werner Wothke, maintenance (http://www.smallwaters.com) Brad Hanson (http://www.b-a-h.com/) See the file LICENSE for information on usage and redistribution.

Copyright (C) 2008, Werner Wothke Copyright (c) 2000-2001, Bradley A. Hanson

Definition in file Start3PL.h.

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